Bottom Line:
Separate MRI images were merged with the SPECT images. (201)Tl olfactory migration was also correlated with the volume of the olfactory bulb determined from MRI images, as well as with odor recognition thresholds measured by using T&T olfactometry.The migration of (201)Tl to the olfactory bulb was significantly correlated with odor recognition thresholds obtained with T&T olfactometry and correlated with the volume of the olfactory bulb determined from MRI images when all subjects were included.Assessment of the (201)Tl migration to the olfactory bulb was the new method for the evaluation of the olfactory nerve connectivity in patients with impaired olfaction.

Purpose: The aim of this study was to assess whether migration of thallium-201 ((201)Tl) to the olfactory bulb were reduced in patients with olfactory impairments in comparison to healthy volunteers after nasal administration of (201)Tl.

Procedures: 10 healthy volunteers and 21 patients enrolled in the study (19 males and 12 females; 26-71 years old). The causes of olfactory dysfunction in the patients were head trauma (n = 7), upper respiratory tract infection (n = 7), and chronic rhinosinusitis (n = 7). (201)TlCl was administered unilaterally to the olfactory cleft, and SPECT-CT was conducted 24 h later. Separate MRI images were merged with the SPECT images. (201)Tl olfactory migration was also correlated with the volume of the olfactory bulb determined from MRI images, as well as with odor recognition thresholds measured by using T&T olfactometry.

Results: Nasal (201)Tl migration to the olfactory bulb was significantly lower in the olfactory-impaired patients than in healthy volunteers. The migration of (201)Tl to the olfactory bulb was significantly correlated with odor recognition thresholds obtained with T&T olfactometry and correlated with the volume of the olfactory bulb determined from MRI images when all subjects were included.

Conclusions: Assessment of the (201)Tl migration to the olfactory bulb was the new method for the evaluation of the olfactory nerve connectivity in patients with impaired olfaction.

pone-0057671-g002: SPECT-MRI fusion image (coronal view) of nasal 201Tl migration to the olfactory bulb.White arrows indicate the olfactory bulb and olfactory nerve. (A) A 60-year-old healthy male volunteer. (B) A 44-year-old female with hyposmia after head trauma. (C) A 42-year-old female with hyposmia after upper respiratory tract infection. (D) A 67-year-old female with hyposmia due to chronic rhinosinusitis. The index of 201Tl migration from the olfactory epithelium to the olfactory bulb in the selected subjects was shown in Table 2.

Mentions:
Representative cases are shown in Fig. 2 and summarized in Table 2. A 60-year-old healthy male volunteer showed good olfactory function and a high level of nasal 201Tl migration to the olfactory bulb (Fig. 2A, Table 2), a 44-year-old female with hyposmia after head trauma showed severe olfactory dysfunction and a low level of nasal 201Tl migration to the olfactory bulb (Fig. 2B, Table 2), a 42-year-old female with hyposmia after upper respiratory tract infection showed moderate olfactory dysfunction and a low level of nasal 201Tl migration to the olfactory bulb (Fig. 2C, Table 2), and a 67-year-old female with hyposmia from chronic rhinosinusitis showed moderate olfactory dysfunction and a low level of nasal 201Tl migration to the olfactory bulb (Fig. 2D, Table 2). MRI images of the representative cases are shown in Fig. 3.

pone-0057671-g002: SPECT-MRI fusion image (coronal view) of nasal 201Tl migration to the olfactory bulb.White arrows indicate the olfactory bulb and olfactory nerve. (A) A 60-year-old healthy male volunteer. (B) A 44-year-old female with hyposmia after head trauma. (C) A 42-year-old female with hyposmia after upper respiratory tract infection. (D) A 67-year-old female with hyposmia due to chronic rhinosinusitis. The index of 201Tl migration from the olfactory epithelium to the olfactory bulb in the selected subjects was shown in Table 2.

Mentions:
Representative cases are shown in Fig. 2 and summarized in Table 2. A 60-year-old healthy male volunteer showed good olfactory function and a high level of nasal 201Tl migration to the olfactory bulb (Fig. 2A, Table 2), a 44-year-old female with hyposmia after head trauma showed severe olfactory dysfunction and a low level of nasal 201Tl migration to the olfactory bulb (Fig. 2B, Table 2), a 42-year-old female with hyposmia after upper respiratory tract infection showed moderate olfactory dysfunction and a low level of nasal 201Tl migration to the olfactory bulb (Fig. 2C, Table 2), and a 67-year-old female with hyposmia from chronic rhinosinusitis showed moderate olfactory dysfunction and a low level of nasal 201Tl migration to the olfactory bulb (Fig. 2D, Table 2). MRI images of the representative cases are shown in Fig. 3.

Bottom Line:
Separate MRI images were merged with the SPECT images. (201)Tl olfactory migration was also correlated with the volume of the olfactory bulb determined from MRI images, as well as with odor recognition thresholds measured by using T&T olfactometry.The migration of (201)Tl to the olfactory bulb was significantly correlated with odor recognition thresholds obtained with T&T olfactometry and correlated with the volume of the olfactory bulb determined from MRI images when all subjects were included.Assessment of the (201)Tl migration to the olfactory bulb was the new method for the evaluation of the olfactory nerve connectivity in patients with impaired olfaction.

Purpose: The aim of this study was to assess whether migration of thallium-201 ((201)Tl) to the olfactory bulb were reduced in patients with olfactory impairments in comparison to healthy volunteers after nasal administration of (201)Tl.

Procedures: 10 healthy volunteers and 21 patients enrolled in the study (19 males and 12 females; 26-71 years old). The causes of olfactory dysfunction in the patients were head trauma (n = 7), upper respiratory tract infection (n = 7), and chronic rhinosinusitis (n = 7). (201)TlCl was administered unilaterally to the olfactory cleft, and SPECT-CT was conducted 24 h later. Separate MRI images were merged with the SPECT images. (201)Tl olfactory migration was also correlated with the volume of the olfactory bulb determined from MRI images, as well as with odor recognition thresholds measured by using T&T olfactometry.

Results: Nasal (201)Tl migration to the olfactory bulb was significantly lower in the olfactory-impaired patients than in healthy volunteers. The migration of (201)Tl to the olfactory bulb was significantly correlated with odor recognition thresholds obtained with T&T olfactometry and correlated with the volume of the olfactory bulb determined from MRI images when all subjects were included.

Conclusions: Assessment of the (201)Tl migration to the olfactory bulb was the new method for the evaluation of the olfactory nerve connectivity in patients with impaired olfaction.